Related Experiment Video
Updated: Mar 10, 2026

Obtaining Highly Purified Toxoplasma gondii Oocysts by a Discontinuous Cesium Chloride Gradient
Published on: November 3, 2009
Lifelong Persistence of Toxoplasma Cysts: A Questionable Dogma?
Solène Rougier1, Jose G Montoya2, François Peyron1
1Hospices Civils de Lyon, Institut de Parasitologie et Mycologie Médicale, Hôpital de la Croix Rousse, F-69317 Lyon, France.
Abstract:
It is believed that infection by Toxoplasma gondii triggers a lifelong protective immunity due to the persistence of parasitic cysts which induce immunoprotection against reinfection. A review of the scientific literature since the 1950s did not yield any definitive data regarding the duration of cysts in the host or the presence of lifelong protective immunity, which led us to question this dogma. We put forward the hypothesis that sustained immunity to T. gondii requires repeated antigenic stimulations. The decline of seroprevalence recently observed in many countries might contribute to explain the loss of immunity. We address the potential consequences of this phenomenon, should it persist and worsen.
Related Concept Videos
Symbiosis
Diversity of Protists II
Long-term Potentiation
Hebbian LTP
LTP can occur when...
Long-term Potentiation

